Phase 1: Upfront Engineering and Alpha Electronic Engineering

Key Activities

1. Requirements Gathering
The initial phase involved collaborative sessions to refine and finalize the project requirements. These were documented in a Product Requirements Document (PRD), which became the guiding framework for the design and development process.

• Physical Design Envelope: The electronics were constrained to fit within a compact, specified physical envelope.
• Power Requirements: Defined input voltage range and output current specifications (continuous and peak).
• Thermal Dissipation: Strategies for effective heat dissipation were established.
• Input / Output Ports: Supported external triggers, hall effect sensors, encoders, and serial communication interfaces.
• Commutation Modes: Evaluated and selected between sinusoidal, trapezoidal, or hybrid commutation modes.
• Low-Speed Torque Requirements: Ensured competitive performance at low speeds.
• Back EMF Sensing Strategy: Selected a robust, industry-standard sensing approach.
• Target Pricing: Balanced cost, performance, and design timelines.
• Environmental Constraints: Addressed requirements for autoclave sterilization and high-temperature endurance.

2. Platform Selection
Evaluated Brushless DC (BLDC) reference designs from various semiconductor manufacturers to recommend a platform aligned with the project objectives.

3. Major Component Selection
Critical components were selected, such as:

• Power MOSFETs
• Gate Drivers
• Current Sense Amplifiers

4. Bench Testing
Evaluation kits for the selected platform were acquired and tested for viability. Bench tests ensured compatibility and reliability of major components. Results were documented and shared for validation.

5. Alpha Electronic Engineering

• Schematic Design: Industry-leading design software was used to create the schematics, leveraging reference designs and prototype circuitry.
• Minor Component Selection: Transistors, capacitors, resistors, and other components were specified after schematic approval.
• PCB Layout: Designed an Alpha PCB that adhered to the physical constraints of the 3D envelope. Provided 3D step files for integration into CAD platforms.
• Fabrication and Testing: Coordinated with a PCB fabrication house specializing in low-volume prototypes. A batch of five boards was produced for Alpha testing.
• Electrical Testing: Conducted comprehensive tests to verify board functionality using basic firmware for initial validation.

Assumptions

• BLDC motors, gearheads, encoders, and predicate handtools were provided for study and testing.
• A customized controller was developed specifically for the laparoscopic handtool.
• Reference designs from semiconductor vendors were utilized to avoid the risks and costs associated with fully custom driver development.
• Current and voltage monitoring requirements were assumed to be low accuracy for gross error detection, with specific needs to be defined during the upfront design phase.
• Active participation in Alpha testing provided valuable feedback for iterative improvements.
• A maximum of two Alpha iterations was anticipated, with flexibility for an additional iteration if necessary.

Challenges Addressed

• Ensured seamless integration within the compact physical design envelope.
• Balanced cost constraints with high-performance standards.
• Developed hardware capable of withstanding sterilization and operating at elevated temperatures.

Outcome

The project successfully delivered a functional Alpha prototype of the laparoscopic robotic handtool controller. Benchmarked against industry standards, the controller demonstrated competitive performance in low-speed torque, thermal management, and integration. The iterative process ensured alignment with the project’s vision and product goals.

This case study highlights the collaborative effort, robust engineering practices, and customer-centric approach in the design and development of specialized surgical robotic systems.